The invention relates to an image projection system comprising, in this order, an illumination system with a radiation source and an image display system with at least one reflecting image display panel for modulating, with image information, an illumination beam to be supplied by the illumination system, and a projection lens system, a polarization-sensitive beam splitter being arranged between the illumination system and the image display panel.
An image projection system of the type described in the opening paragraph is known, for example, from European patent specification EP 0 467 447, to which U.S. Ser. No. 08/976,517 corresponds. The image projection system described in this specification comprises an illumination system for supplying an illumination beam and an image display system with reflective image display panels for modulating this light beam in conformity with image information to be projected. The display panel may be, for example a liquid crystalline display panel comprising a layer of liquid crystalline material which is provided with a two-dimensional array of pixels which are driven by means of, for example electrodes.
In the known reflective LCD projection systems, the different directions of polarization are separated from each other by means of a polarization-sensitive beam splitter. The part of the light modulated by the display panel, which part must give rise to dark pixels in the image, in other words, the light which is modulated by pixels of the display panel corresponding to dark pixels in the image, is deflected from the light path by the beam splitter and is thus lost. This is at the expense of the peak brightness in the image.